Gatineau Police say a three-month-old baby has died and a 20-month-old baby has serious injuries after an overnight fire.

Fire crews were called to Paluck Street in the Buckingham area around 2 a.m.

Police say five people were injured, including three children.. Officials confirm the three-month-old was discovered on scene unresponsive, in life-threatening condition. A 31-year-old man, 28-year-old woman, 20-month-old child and 12-year-old were taken to hospital with injuries sustained in the fire.

Neighbours watched in horror as flames and smoke filled the night sky. Flames spread in front of a home on Rue Paluck with a young family of five inside. When firefighters arrived, they found fire inside a pick-up truck parked on the driveway beside the home; where the family is believed to have lived for 8 years.

“I'm scared for the kids,” said neighbour Joanne Lawrence. “It makes my heart go...It's hard, very hard.”

André Cyr lives behind the home, he witnessed the aftermath when crews arrived to control the fire.

“Fire in the truck and there was a fire in the house,” Cyr said. “So go figure what happened.”

Firefighters say two ladders were used to rescue the family. A man in his thirties, a woman believed to be his wife and three children were pulled out; all taken to hospital.

"Three teams of paramedics were on scene,” said Robyn Marcotte, director of operations of Gatineau Ambulance Service.

“Baby was in cardiac arrest.” Marcotte wouldn’t reveal the identity of gender of the 3-month-old but said paramedics were successful in resuscitating the child on the way to hospital.

Hearing children lived in the home was surprising for neighbour Lise Monette. “I never saw kids there, I didn’t even know they had three kids,” said Monette.

The man, believed to be the father of the kids, suffered serious burns to his body, according to officials. The woman and the two other children treated for smoke inhalation and burns.

“For the mother and older children, it looks fine, but time is going to tell if everything is going to be fine for them,” said Marcotte.

Criminal investigation underway after a fire in Gatineau involving a couple and three children; neighbours say a newborn has passed away from injuries sustained in the fire ⁦@ctvottawapic.twitter.com/WqNIp9yQ9S

— Mike Arsalides (@MArsalidesCTV) August 31, 2019

The fire is believed to have started in a pick-up truck on the driveway outside the home; officials won't say how the fire started, who started it and whether criminal charges will be laid.

Gatineau Fire estimates damage at approximately $53,775.